$(window).addEvent('domready',function(){
    $$("#postbody td:nth-child(2)").each(function(td){
        td.store('ulElement',td.getElement('ul'));
        td.addEvents({
            'mouseover':function(){
                this.retrieve('ulElement').setStyle('visibility','visible');
            },
            'mouseout':function(){
                this.retrieve('ulElement').setStyle('visibility','hidden');
            }
        });
    });

});